Every year, thousands of individuals undergo total hip replacement (THR) as a result of degeneration or otherwise excessive damage to the acetabulum. This damage causes irregular and/or painful articulation between the femoral head and the acetabulum during normal movement of the leg and hip. It therefore becomes necessary to replace the damaged articulation site with a prosthetic implant that can adequately manage the normal forces encountered at the site while maintaining a sufficient range of motion between the femur and pelvic girdle.
A THR procedure typically involves resecting a portion or all of the acetabulum so that a prosthetic component mimicking the acetabulum can be installed in its place. The cup is contoured and constructed such that its functionality closely resembles that of the native acetabulum. The femoral head may also be partially or fully resected to accommodate a prosthetic stem and head that will articulate with the prosthetic cup.
The efficacy of current acetabular cups lies in the ability to retain a secure connection between the cup and the pelvic girdle. By maintaining a strong connection, the ability of the surrounding bone to heal is improved, as is the reliability of the replaced articulation site. However, due to constant and variable articulation between the femoral head and the acetabular cup, the cup may loosen over time. This movement may contribute to a weakened articulation site or may make the femoral head susceptible to slippage out of the cup, resulting in severe pain and discomfort. Another contributing factor to the performance decline of an acetabular cup can be the complex anatomical geometry of the pelvic girdle. This geometry may make it difficult to ensure a lasting, rigid connection between the cup and the bone. Current cups use bone cement, friction, and/or fasteners/screws to directly secure the cup to the pelvic girdle. For the above reasons, these fastening constructions can fail to ensure proper fixation of the cup within the acetabulum.
Accordingly, there is a need for an apparatus and method for ensuring that prostethic acetabular cups are securely fitted to the pelvic girdle to ensure proper healing and reliable articulation with the femoral head.